Yeah, this is a very big change in policy, and I suspect it might catch out Mandrill customers who don't read the fine print. The privacy policies for a couple of web applications I work with, for example, are incompatible with this new policy.
Guys, are you sure about this? Mailchimp subscribers and Mandrill users are not the same thing... Otherwise the Mailchimp cost would skyrocket, as they charge users in terms of subscribers amount